1. Field of the Invention
The present invention relates an apparatus for driving a gyroscope sensor usable in a mobile terminal, and more particularly, to an apparatus for driving a gyroscope sensor capable of rapidly stopping driving of a gyroscope sensor by driving it in a reverse direction during the driving thereof.
2. Description of the Related Art
Generally, a gyroscope sensor is a sensor that uses the Coriolis force (Fc) of vibrating objects to measure angular velocity.
In this case, the Coriolis force of the gyroscope sensor depends on the following Equation 1.Fc=2mVΩ  Equation 1
Where Fc: Coriolis force, m: mass, V: velocity, Ω: angular velocity.
Referring to Equation 1, velocity V is generated by vibrating the gyroscope sensor with a driving signal to generate velocity V to measure the Coriolis force Fc. In this case, when the velocity V defined by the driving and the sensed Coriolis force Fc are known, the angular velocity Ω can be calculated, since a mass m is already known.
That is, since the angular velocity Ω is represented by ‘Fc/2mV’, the Coriolis force Fc is measured while the mass m of the object is driven at a constant velocity V, thereby making it possible to obtain the angular velocity Ω.
In particular, the Coriolis force Fc, the velocity V, and the angular velocity V are a vector in a vertical direction therebetween. For example, in order to obtain an angular velocity Ωz in a z direction, a Coriolis force Fc_y in a y direction may be measured by giving a velocity Vx in an X direction. In addition, in order to measure angular velocities Ωx and Ωy in x and y directions, Coriolis forces Fc_y and Fc_x in y and x directions may be measured by giving a velocity Vz in a z direction.
That is, in order to measure angular velocities in several directions, the vibrational direction of the vibrating object should be changed, and in order to increase a measuring frequency bandwidth of an angular velocity, a sampling rate should be increased.
For example, in order to obtain the measuring frequency bandwidth of 0 to 100 Hz, the sampling should be performed 200 times for at least 1 second.
Generally, the gyroscope sensor drives an object in a z-axis by vibrating the object having a high quality factor Qs, thereby measuring the angular velocity in the x and y axes. Thereafter, the gyroscope sensor drives the object in the x-axis direction by changing the movement of the object in order to measure a z-axis, thereby needing the driving stopping time for changing the direction.
However, the apparatus for driving the gyroscope sensor according to the related art does not include special technical apparatuses for stopping the gyroscope sensor during the driving of the gyroscope sensor, such that stopping the gyroscope sensor during the driving of the gyroscope sensor is time consuming. As a result, the apparatus for driving the gyroscope sensor according to the related art has a long settling time, such that it is not suitable to apply to a multi-axis gyroscope sensor.